I wouldn't say that Rudolph is innocent. There just isn't enough information to know for sure one way or the other. You had a lot of other players around there, and none of them claimed to have heard it. That doesn't mean it didn't happen, but it does mean that we're left with an uncorroborated allegation in circumstances where you'd think there would be some corroboration. And if the other players didn't hear it...why are so many people certain that "the NFL" did?
If someone put a gun to my head and asked me to guess, I'd believe Garrett. But you can't punish Rudolph for this given the complete lack of corroboration.